gametofyytistä

Gametofyytti is the haploid multicellular stage in the life cycle of plants and algae that alternates with the sporophyte generation. It is the stage responsible for producing gametes through mitosis. The gametophyte generation develops from a spore. In some organisms, such as mosses and ferns, the gametophyte is the dominant, free-living generation. In others, like seed plants, it is greatly reduced and dependent on the sporophyte. The fusion of male and female gametes (fertilization) from two gametophytes or from the same gametophyte results in the diploid zygote, which develops into the sporophyte. The sporophyte then produces spores through meiosis, which in turn develop into new gametophytes, completing the alternation of generations. The structure and size of the gametophyte vary widely across different plant groups, reflecting their evolutionary adaptations to terrestrial or aquatic environments.